Ultra-high voltage (UHV) metal oxide semiconductor field-effect transistor (MOSFET) devices are utilized in integrated circuits mainly for switching applications due to their high efficiency relative to other power semiconductor devices such as insulated gate bipolar transistors and thyristors. Breakdown voltage of a UHV MOSFET device is related to a thickness of a layer of buried oxide (BOX) which surrounds the UHV MOSFET device, as well as wafer thickness. Increasing the BOX thickness to increase breakdown voltage can increase defect densities and reduce manufacturing throughput.